S. Shenkov

Complex formation between polymethacrylic acid and copolymers of adipic acid with poly(ethylene glycol) in aqueous solution

Abstract The complex formation between polymethacrylic acid (PMAA) and the copolymers of adipic acid (AdA) with poly(ethylene glycol) (PEG) in dilute solution has been studied. The hydrophobic AdA fragments break the continuous cooperative hydrogen bonds between the polymer components in the polycomplex being however the factor that stabilizes the polycomplex (PMAA.AdA/PEG). If the AdA/PEG copolymers are of one and the same chain length the copolymer having more AdA hydrophobic fragments exhibits greater complex forming ability.

Complexation of poly(methacrylic acid) with poly(ethylene glycol) nonionic surfactants in aqueous solutions

Abstract The interaction between poly(methacrylic acid) (PMAA) and surfactants based on poly(ethylene glycol) in aqueous solutions has been studied by viscometry and potentiometric titration. The interaction proceeds in two stages with increasing concentration of the surfactants. At first, the polycomplex (PMAA surfactant) is formed. The structural state of the surfactant in the polycomplex depends on the hydrophilic-hydrophobic balance of the surfactant. In the second stage at higher concentration of the surfactant, the polycomplex binds the micelles, forming an associate with two possible structures.

Aggregation behavior and in vitro biocompatibility study of octopus-shaped macromolecules based on tert-butylcalix[4]arenes.

A series of products based on tert-butylcalix[4]arene have been synthesized by anionic polymerization of ethylene oxide. The resulting products are amphiphilic octopus-shaped macromolecules, consisting of a hydrophobic calix[4]arene core and four arms of hydrophilic poly(ethylene oxide) chains. In aqueous solutions the polyoxyethylated tert-butylcalix[4]arenes were found to self-associate above certain CMC determined by dye solubilization technique. The light scattering study reveals that the polyoxyethylated tert-butylcalix[4]arenes form aggregates of narrow size distribution and hydrodynamic diameters ranging from about 155 to 245 nm and aggregation numbers from tens to hundreds macromolecules per particle depending on the degree of polymerization of the PEO chains. An in vitro biocompatibility study showed that the tested compounds are practically devoid of intrinsic cytotoxic and hemolytic effects and moreover they failed to modulate the mitogen-induced interleukin-2 release from the human T-lymphocyte cell line Jurkat E6-1. Taken together the excellent in vitro biocompatibility profile and the favorable physicochemical characteristics of the tested polyoxyethylated calix[4]arenes give us reason to consider them as promising for further evaluation as drug delivery platforms.

Complexation between poly(methacrylic) and poly(acrylic) acids and star‐shaped poly(ethylene glycol) based on pyrogallol

Complex formation between polymethacrylic (PMAA) and polyacrylic acids, and star-shaped poly(ethylene glycol) prepared by ethoxylation of pyrogallol (Pyr-PEG) has been studied viscometrically and by potentiometric titration in water solution. The competitive ability of Pyr-PEG and of the derivatives of the ethoxylation of phenol and hydroquinone in complex formation with PMAA has been compared by UV spectroscopy. Pyr-PEG turns out to be the weakest competitor because of its chemical structure.

Competitive complex forming reactions between monosubstituted and nonsubstituted poly(ethylene glycol)s with poly(methacrylic) acid

A competitive complex forming reaction between a number of monosubstituted poly(ethylene glycol)s (PEG*) containing a hydrophobic group of differing chemical nature and nonsubstituted PEG of various molecular weights with poly(methacrylic acid) (PMAA) was studied. A UV spectroscopy method was used. During the transfer of the hydrophobic chromophoric group from the aqueous medium into the hydrophobic domains of the polycomplex (PMAA.PEG*), a bathochromic effect was observed. The introduction of a hydrophobic group into the PEG chain leads to stabilization of the polycomplex (PMAA.PEG) that is formally the same as growing the chain length of PEG. The polymerization degree of PEG having the same competitive power as PEG* can be used as the peculiar scale of the complex forming ability of PEG* in the complexation with PMAA.

THE REACTION OF DIMETHYL HYDROGEN PHOSPHONATE AND AMINOALCOHOLS

Abstract The interaction between dimethyl hydrogen phosphonate (DMHP) and aminoalcohols was examined. It was found that at the temperature of 80°C the basic reaction is that of alkylation of the aminoalcohols. The structure of the end products was proved by the aid of 1H- and 31P-NMR spectroscopy.

Nonspecific interactions in polymer-polymer reactions—5. Reactions of macromolecular substitution in complexation between poly(methacrylic acid) and mono-substituted poly(ethylene glycol)s

Abstract A competitive complex forming reaction between poly(methacrylic acid) (PMAA) and a number of monosubstituted poly(ethylene glycol)s (PEG∗), containing a hydrophobic group of differing chemical nature has been studied by u.v. spectroscopy. The method is based on the fact that during the transfer of the hydrophobic chromophoric group from the aqueous medium into the hydrophobic domains of the polycomplex ( PMAA · PEG ∗ ) a bathochromic effect is observed.

Synthesis of phosphorus-, silicon- and chlorine-containing oligomers

Abstract Phosphorus-, silicon- and chlorine-containing oligomers were synthesized by the dealkylation of methyl esters of phosphonic and phosphoric acids with dimethyldichlorsilane or diphenyldichlorsilane. It was established that the α-carbon atom of the methoxy group acts as an electrophilic centre. The structures of the products were established by 1H- and 31P-NMR spectroscopy and GPC chromatography.

Phosphorus-containing rigid polyurethane foams—II. Modifiers based on trimethyl phosphate

Abstract Phosphorus-containing modifiers, alkanolammonium salts, obtained by interaction of trimethyl phosphate and aminoalcohols, are used to obtain rigid polyurethane foams (PUFs) with various phosphorus contents. Some of their physical mechanical properties and resistance to combustion are examined. It is shown that these phosphorus-containing modifiers are effective additives for improving fire resistance of rigid PUFs. For a low concentration of phosphorus-containing modifier, the rigid PUFs have high fire resistance and good physical and thermomechanical properties.

Synthesis and Characterization of Partially Substituted at Lower Rim Phosphorus Containing Calix(4)arenes

The synthesis and characterization of several new phosphorus-containing partially lower rim substituted derivatives of 5,11,17,23-tetra(t-butyl) calix(4)arene (I) and 5,11,17,23-tetra(t-octyl)calix(4)arene (II), namely 5,11,17,23-tetra(t-butyl)-25,27-dihydroxy-26,28-bis(diphenylphosphinoyl-oxy) calix(4)arene (IV); 5,11,17,23-tetra(t-butyl)-25-hydroxy-26,27,28-tris(tetramethyldiamido-phosphinoyl-oxy) calix(4)arene (Vb); 5,11,17,23-tetra(t-butyl)-25,27-dihydroxy-26,28-bis(dimethyl-phosphinoyl-methoxy) calix(4)arene (VI); 5,11,17,23-tetra (t-octyl)-25,27-dihydroxy-26,28-bis(dimethyl-phosphinoyl-methoxy) calix(4)arene (VII) are reported. The structure of the synthesized calix(4)arene derivatives are identified and confirmed by elemental analysis, IR, 1H, 13C, 31P{1H} NMR spectroscopy and mass spectrometry as and X-ray crystallographic analysis of 5,11,17,23-tetra(t-butyl)-25,27-dihydroxy-26,28-bis(dimethyl-phosphinoyl-methoxy) calix(4)arene VI. According to the NMR spectra, all calix(4)arenes are in cone conformation.